1. Field of the Invention
The present invention generally relates to a female type terminal for a large current, an assembling method of the female type terminal, and a connector housing for the female type terminal and, more particularly to a female type terminal having a spring contact, which is put into contact with a male type terminal in a terminal body, and used for charging a battery of an electric vehicle or for connecting the battery to another apparatus, an assembling method of the female type terminal, and a connector housing to accommodate the female type terminal.
2. Description of the Related Art
As a conventional female type terminal for a large current, a female type terminal shown in FIG. 8A exists, for example.
FIG. 8A shows the female type terminal applied to an electric vehicle.
In FIG. 8A, a reference numeral 100 indicates the conventional female type terminal which has a cylindrical spring contact 120 which is put into contact with a rod-like male type terminal 200 (FIG. 8B) to be inserted in a cylindrical terminal body 110.
The terminal body 110 is formed by boring a good conductive metal, such as aluminum, and an introductory opening 111 with substantially the same diameter as the male type terminal 200 opens at the end thereof. The introductory opening 111 is tapered so as to easily insert the male type terminal 200 into the terminal body 110.
A space to receive the male type terminal 200 continues from the introductory opening 111, and an accommodating portion 110A having substantially the same diameter as the spring contact 120 is formed as a part of the space. By forming the accommodating portion 110A having a larger diameter than that of the male type terminal 200 on the way of the space, the front and rear inner walls of the accommodating portion 110A function as first and second stopping walls 112, 113 having smaller diameters than that of the spring contact 120.
On the rear of the terminal body 110 a fastening portion 110B of an electrical wire (not shown) continues.
On the other hand, the spring contact 120 has a number of arched leaf spring pieces 121 which are connected with connecting portions 122. The spring contact 120 has a cylindrical shape.
When such a spring contact 120 is accommodated in the accommodating portion 110A of the terminal body 110, the connecting portions 122 abut against an end surface 112a of the first stopping wall 112 and an end surface 113a of the second stopping wall 113, whereby the spring contact 120 is held in the accommodating portion 110A.
With respect to the above-described conventional female type terminal 100, however, since the female type terminal 100 and the male type terminal 200, being both for a large current, and large-sized and large-weighted differently from a female type terminal and a male type terminal for general and small current use, resistance, force, and shock for insertion or drawing of the male type terminal against the female type terminal is large. Despite the above, since the spring contact 120, being relatively weak and easily broken, exists in the female type terminal 100, various problems described below exist.
First, as shown in FIG. 8B, since there are an edge between the introductory opening 111 and the first stopping wall 112, i.e. the boundary 111b, and an end edge 112b of the first stopping wall 112 in the conventional female type terminal 100, the outer surface of the male type terminal 200 rubs against these edges when the male type terminal 200 is inserted aslant into or drawn aslant from the introductory opening 111, and therefore the plating on the outer surface of the male type terminal 200 would come off.
That is, since the female type terminal 100 and the male type terminal 200 for a large current are large-sized and large-weighted differently from a female type terminal and a male type terminal generally used, too large frictional resistance against the edges (the boundary 111b and the end edge 112b) of the female type terminal 100 arises when the male type terminal 200 is inserted aslant or drawn aslant, whereby the plating of the male type terminal 200 would come off.
Generally, the plating processed on a terminal improves conductivity thereof, lowers insertion and drawing resistance thereof, and further prevents the terminal from becoming rusty.
Accordingly, the coming-off of the plating on the male type terminal 200 by the insertion or drawing of the male type terminal 200, the conductivity thereof lowers, the insertion and drawing resistance of the female type terminal 100 increases, and the male type terminal 200 would become rusty.
Secondly, since the female type terminal 100 is accommodated in a terminal accommodating chamber of a connector housing (not shown) and forms a connector, the end of the male type terminal 200 inserted straight into the female type terminal 100 strikes against the leaf spring piece 121 of the spring contact 120, and in case the female type terminal 100 has been set aslant in the terminal accommodating chamber, the leaf spring piece 121 would be broken.
Thirdly, since the spring contact 120 has to pass through the introductory opening 111 and the first stopping wall 112, both having a smaller diameter than that of the spring contact 120, when the spring contact 120 is inserted into the accommodating portion 110A of the terminal body 110, the spring contact 120 has to be compressed to make the diameter smaller and, while keeping the state, is passed through the introductory opening 111 and through the first stopping wall 112, and is inserted in the accommodating portion 110A.
Therefore, the assembly work of the female type terminal would require practice and time; in other words, the assembly work could not be done efficiently.
Fourth, through the terminal body 110 of the above conventional female type terminal 100 can be formed by boring a metal, another terminal body 310 can be formed by cylindrically bending a metal plate 300 by the press work, as shown in FIGS. 9A, 9B and 9C.
Further, since the female type terminal for a large current is large-sized and large-weighted, it is characterized in having such a spring contact accommodated in the terminal body, and has the above-described problems such as coming-off of the plating of the male type terminal, breakage of the spring contact, difficulty of the assembly work, or the like, therefore, fully effective use of the cap member would be required in order to solve all of the problems.
Also, as shown in FIG. 10A, a gap L1 arises between the abutting surfaces 301,302 by "spring-back" after the press work.
And, in case that the gap L1 is larger than a width L2 of the leaf spring piece 121 of the spring contact 120, the leaf spring piece 121 of the spring contact 120 is put in the gap L1 and broken when a male type terminal (not shown) is inserted in the terminal body 310 (refer to FIG. 10B).
Further, if the pressing force is strengthened so as to prevent the gap of the abutting surfaces 301,302, the abutting surfaces 301,302 do not meet each other, which forms a wrong terminal body in dimension.
Here, Japanese Patent Application Laid-open No. 6-14472 proposes a general connector 400 having a ferrule (a cap member) 411 at the end of a female type terminal 410 as shown in FIGS. 11A, 11B, and 11C.
As shown in FIG. 11C, the ferrule 411 abuts against lances 422 when a female type terminal 410 is accommodated in a terminal accommodating chamber 421 of a connector housing 420, whereby the female type terminal 410 is prevented from shifting rearward, that is, from coming out of the terminal accommodating chamber 421.
And, the ferrule 411 guides a pin-shaped terminal 430 of the mating connector into the female type terminal 410.
With respect to the above general connector being merely equipped with the cap member at the end of the female type terminal for a large current, when the large sized and large weighted male type terminal is inserted or drawn, the cap member is apt to drop out.
Further, since the female type terminal for a large current is large-sized and large-weighted, is characterized in having such a spring contact accommodated in the terminal body, and has the above-described problems such as coming-off of the plating of the male type terminal, breakage of the spring contact, difficulty of the assembly work, or the like, therefore, fully effective use of the cap member would be required in order to solve all of the problems.